Lou et al showed that SHOX2 and RASSF1A gene methylation in BALF were significantly different between the cancer group (n = 284) and control group (n = 38).[17] Other studies have also confirmed that combined detection of these 2 genes can assist in diagnosing lung cancer, with sensitivities ranging from 71.5% to 83.2% and a specificity of 90% to 100%.[18,19] However, acquiring BALF is clinically uncomfortable for patients and may lead to complications such as bleeding, laryngeal edema or hoarseness, and asthma attacks. The gene discussed is RASSF1; the disease is cancer.